CO2 Capture - Technicalities of attaching a capture plant to Eskom s power stations

Transcription

1 CO2 Capture - Technicalities of attaching a capture plant to Eskom s power stations Barry MacColl GM Research, Testing and Development Transmission & Sustainability Division

2 South Africa Electricity Capacity in 2030 Committed 1125 New Existing Committed Decomm. (10902) New Existing 1800 New 9600

3 The Integrated Resource Plan 2010 where CO 2 emissions remain below 275 Mt p.a. from 2025 Mt CO2 p.a Long-term emission target of 275 Mt p.a. OCGT/CCGT Additional new coal Committed new coal Existing coal g/kwh 821 g/kwh 600 g/kwh -34% Source: DoE presentation to Cabinet 3

4 Capture Ready requirements for Kusile Power Station In March 2008 a revised RoD was issued for Kusile Power Plant which included a requirement for Kusile to be built Carbon Capture Ready. The way this condition was expressed, reflected recognition for the initial power plant design (pulverised coal) the international level of technology development (several options under development) the status of local information with respect to storage potential (no atlas at that time) The IEA s definition, in 2007, that a CO 2 capture-ready power plant is a plant which can include CO 2 capture when the necessary regulatory or economic drivers are in place was used to identify the essential pre-requisites. Stipulating CCR in the RoD is not considered to be a sufficient regulatory framework for the actual deployment of CCS transport and storage are still lacking. Particulate matter control, SOx levels, plant layout (access to flue gas, scrubber, power, compression and cooling) and land requirements have been factored into the design.

5 Strategic Partnerships Access to a lot of good people Current work and partnerships IEA CCC International Energy Agency Clean Coal Centre CSLF Carbon Sequestration Leadership Forum SACCCS South African Centre for Carbon Capture and Storage EPRI Electric Power Research Institute, Coal fleet for tomorrow SASOL Regular strategic alignment sessions Energy Technology Perspectives - (High Efficiency Low Emissions Coal Roadmap); Implementing Agreement on Greenhouse Gas (GHG) R&D (via the Coal Industry Advisory Board, CIAB) South African Coal Roadmap Research Agreements under consideration GCCSI - Global Carbon Capture and Storage Institute BIG CCS Norwegian Multinational Research Collaboration OCTAVIUS Optimisation of CO2 Trapping Allowing Verification at Utility Scale (European Commission FP7 cooperation) 5

6 We also have access to a lot of good material

7 Typical CCS Retrofit Requirements

8 OCTAVIUS BASE CASES & THE SOUTH AFRICAN CONTEXT Gross Electrical power output Steam Parameters Capture Plant Size Units 800MWe Bituminous Coal Case (DOOSAN/E.ON) ROAD Project (E.ON) Porte Tolle(ENEL) South African New Build (ESKOM) South African CO 2 capture Retrofit (ESKOM) MWe gross MS/HR/bar 600/620/ /620/ /612/ /610/ /570/245 MW e Five base cases were selected for evaluation within the OCTAVIUS project with the 800MW e advanced supercritical bituminous coal case being the lead case for this project. 8

9 RETROFIT CONSIDERATIONS Evaluate the impact of different capture plant integration scenarios on plant performance, cost and operability. Undertake high level review and assessment of integration options, ranking each option in terms of anticipated impact on efficiency, CAPEX and flexibility. Technical assessment of the following is considered for each case: Flue Gas tie ins (in and out) Electricity supply Cooling Water Demineralised water Waste Water Controls & Signaling IP/LP steam extraction 1.5 reheat Enhanced capture plant integration Back pressure turbine Reduced LP turbine size 9

10 AMBIENT CONDITIONS Ambient Site Conditions EU Case South African Case Ambient Temperature C Ambient Relative Moisture % Ambient Pressure (absolute) mbar 1, Flue Gas Volume Flows Am 3 /h Cooling Medium Temperature C Condensing Pressure (absolute) mbar 2,585,590 3,258, (dry cooling) Lower efficiency and larger air/gas volumes = Bigger plant to achieve the same output MW Furnace: 17m x 24m PS Medupi, 800 MW Furnace: 16m x 23m 800 MW EU Furnace: 16m x 19m 2015/11/16 10

11 COAL Fuel Data for Solid Fuels (as Received) EU Case Eskom Case Design Coal South African Export South African Local High Heating Value (HHV) MJ/kg Low Heating Value (LHV) MJ/kg Ash g/mj (%) 0.54 (14.15) 2 (35.33) Sulphur g/mj (%) 0.02 (0.52) 0.04 (0.74) Fuel Flow kg/s Higher auxiliary power Milling plant Materials handling (coal, ash, limestone, gypsum) Higher maintenance costs Mill plant wear rate Boiler erosion Another important question outside of this project that needs answering for the South African situation is: Where to build a station with CCS? Next to the coal or next to the storage? 11

12 CONSEQUENCES OF THE DIFFERENCES Consequences Power Island Reduced gross cycle efficiency mainly because of boiler and turbine losses Higher auxiliary power requirements (ACC, mills, altitude, ZLED ) Larger Plant because of higher volume flows Reduced net plant efficiency Capture Plant Higher CO 2 loading per kwh sent out Excess cooling capacity of the ACC cannot be redirected to the capture plant therefore requiring larger cooling installations for retrofit Cooling will be provided by dry cooling technologies Additional ZLED technologies for waste water treatment Eskom Case 44.5% 10.65% 3,3 Mm 3 /h 39.4% 849 g/kwh net EU Case 49.5% 7.9% 2,6 Mm 3 /h 45.5% 763 g/kwh net 12

13 GRID CODE REQUIREMENTS CCS plant will have to be designed to not impede on the ability of power plants to meet there local grid code requirements The South African grid code requirements tend to be more onerous than mainland Europe on account off: The lack of interconnection with other large grids Large concentration of power supply in a single area Size of the grid The main aspects covered by grid codes are: frequency response Islanding capabilities multiple unit trip prevention restart after blackout transformer capabilities 13

14 An expensive investment with wide variance 2015/11/16 14 Source: McKinsey Assessing the Economics

15 It is an expensive Business.

16 Capture is the most expensive component One Kusile 800MW unit will produce ~280 million tons of CO2 in a 50 year life. R20Bn overnight cost. 2015/11/16 16 Source: McKinsey Assessing the Economics

17 Efficiency Loss is high (~30%)

18 High Impact on Operations 1 year outage An Engineering and Economic Assessment of Post-Combustion CO2 Capture for 1100 F Ultra-Supercritical Pulverized Coal Power Plant Applications Phase II Task 3 Final Report EPRI Report

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22 Conclusion The current Country Energy Plan puts us on the right path for CO2 mitigation. We would thus need a compelling reason to do Carbon Capture. We have a wealth of information available to understand the Impact of Capture. Price Efficiency Affect on Operations etc. Generic figures that must be South Africanised. We strongly support the study with the SACCCS and the WB to be done at Kusile.

23 THANK YOU Barry MacColl GM Research, Testing and Development Eskom Tel